1. Field of the Invention
The present invention relates to a parallel fluid heating system and more particularly to a parallel fluid heating system that employs a plurality of fluid temperature responsive flow control valves at the outlet of each of the heaters.
2. Description of the Prior Art
Fluid heating systems in general and hot water heating systems in particular have had very little new development over the last several decades. It is well known to those skilled in the art to connect water heaters in parallel to supply hot water to various water consuming loads. Such systems have been used on naval ships, for example, where the consuming loads may be the laundry, scullery, officers' wash rooms, crews' wash rooms and the like.
Several difficulties have been encountered with these parallel water heating systems. One of these difficulties is that most of the water drawn by a given load is from the nearest water heater irrespective of its outlet water temperature. This is because the piping pressure drop from the load to the nearest heater is smaller than to the other more remote heaters. Therefore, when load demands become large the water temperature to that particular load may drop to a temperature that is considerably below the outlet water temperatures of the other more remote water heaters. Another difficulty with conventional parallel water heater systems is that if one of the heaters fails to heat the water adequately, the cold water it supplies will cool down the water supplied by the other heaters to the load. Still another difficulty encountered with the conventional parallel water heating systems is that if a pipe is ruptured between the heaters and the load there will be a continuous supply of water by the heaters to that rupture.
In accordance with the present invention these difficulties are overcome by employing a plurality of water temperature responsive flow control valves at the outlet of the heaters.